Grignard reagents of organoalkoxysilanes



Patented May 26, 1953 GRIGNARD REAGEN'ES F ORGA Q- ALKOXYSILANES John L. Speier, Pittsburgh, Pa, assignor to Dow Corning Corporation, Midland, Michi, a corporation of Michigan No Drawing. Original application July 26, 1950, Serial No. 176,072. Divided and this applica.- tion March 24, 1952, Serial No. 278,301

2 Claims.

This invention relates to halogenated silicon esters and their derivatives. This application is a division of my copending application Serial No. 176,072 filed on July 26, 1950.

It is an object of this invention to prepare organosilicon compounds which are useful in the preparation of organosilyl alcohols. Another ob ject is to prepare compounds which maybe emplayed in novel organic syntheses. Other objects and advantages will be apparent from the following description.

This invention relatesto' compounds of the formula R3SiO CH2MCl where R. is selected from the group alkyl and .phenyl, and as has a value of3to5.

The organosilicon esters of this invention are prepared by reacting a chlorosilane of the formula RsSiCl with a chloroalcohol'of the formula HO(CHz)aC1. The reaction is best carried out in the presence of a hydrogen chloride acceptor such as ammonia, pyridine,-and other organic. amines. Better yields are obtained by reacting a disilazane of the formula (R331) 2NH with the chloroalcohols. This reaction proceeds according to the equation This latter method is of particular advantage since no solid by-product is obtained. In both of the above methods reaction is preferably carried out at 30 C.

, If desired, inert solvents such as, benzene,;hexane, or diethylether may be employed.

The chlorosilanes employed therein are those in which the R groups may be any alkyl radical or a phenyl radical. The chloroalcohols are those which contain at least three carbon atoms. The carbon chain may contain any number of atoms above three, however, because of commercial availability it is preferred that the chloroalcohol contains from 3 to 5 carbon atoms.

The products of this invention are of particular utility in the preparation of organosilylalcohols, as is more fully described in the applicant's copending application filed concurrently herewith. In general, the alcohols are prepared by reacting the chloroalkoxysilanes of this invention with sodium, lithium, or magnesium. In the case of sodium and lithium, a rearrangement takes place at room temperature according to the equation RsSiO (CH2) :cC1+M R351 (CH2) $0M Thus, a metallic alkoxide is obtained rather than the expected organometallic compound of the 2 type ngsiownzmvr. With magnesium, however, such a rearrangement does not take place at temperatures below 55 C. Hence, it is possible to prepare stable organomagnesium derivatives of the formula, RaSiGQCI-IzMB/IgCI. found unexpectedly that magnesium will not react with compounds of the formula R3SiO'(CH2) 301 but does form Grignard reagents with those compounds where x isabove 3, for example where :c is 4 or 5.

The organomagnesium compounds of the above type are stable at roomtemperature if stored under the usual conditions for keeping Grignard' reagents. These organomagnesium compounds can be reacted with any organiccompound which normally reacts with Grignard reagents. For example, the compounds will react with allyl halides, aldehydes, ketones, esters, nitro compounds, sulfones, acyl. halides, and nitriles.

The resulting product is then hydrolyzed with water to remove the organosilyl group with the concurrent formation of an alcoholic hydroxyl. Since this hydrolysis will occur under the mildest of conditions-,itis now possible to synthesize organic alcohols which heretofore were prepared with great difficulty or notat all.

Furthermore, the above method offers a simple means ofincreasing the chain length of organic compounds by 4 or 5 carbon atoms. With many organic compounds the only way heretofore known for increasing the length of a chain terminated by alcoholic; hydroxyl was by methods which involve the stemwise. addition of one to two carbon atoms at a time, It is now possible to add in one step a hydroxylated chain of from 4 to 5 carbon atoms to an organic compound containing functional groups.

Specific examples of the use of the instant organomagnesium compounds are as follows: (CH3)3SiO-(CH2) sMgCl is prepared by reacting 5-ch1oropentoxytrimethylsilane with magnesium in diethylether. The resulting Grignard reagent is then reacted with benzoyl chloride and the resulting product is hydrolyzed. The process may be represented by the equation (CH SiO(CHz)5MgC1+ CGHEOOC].

It has been- Example 1 440 grams of trimethylchlorosilane in an equal volume of benzene was mixed with 378 grams of 3-chloropropanol-1 and anhydrous ammonia was bubbled through the mixture until the odor of ammonia persisted. The ammonium chloride formed was removed by filtration and the product was distilled to give 513 grams of 3-chloropropoxy-l-trimethylsilane, boiling point 155 C. at 733 mm.,

dag; .9371

and specific refraction .2680.

Example 2 A mixture of 340 grams of pyridine and 527 grams of ethyldimethylchlorosilane was added to 456 grams of 4-chlorobutanol-1 in 1 liter of benzene. After cooling, the mixture was filtered free of pyridine hydrochloride and distilled to yield 392 grams of 4-ch1orobutoxy-1-ethyldimethylsilane, boiling point 94 C. at 24 mm.,

and a specific refraction of .2785.

Example 3 91 grams of hexamethyldisilazane was added to 108 grams of 4-chlorobutanol-1 with external cooling. After the evolution of ammonia had ceased, the mixture was distilled to obtain 143 grams of 4-chlorobutoxy-l-trimethylsilane, boiling point 79 C. at 24 mm.,

specific refraction .2745.

Example 4 201 grams of 5-chloropentanol-1 was mixed with 161 grams of hexamethyldisilazane under vacuum in a cooling bath. After 20 hours the product was distilled to yield 306 grams of 5- chloropentoxy-l-trimethylsilane, boiling point 96 C. at 25 mm.,

Example 5 When phenyldibutylchlorosilane is reacted 4 with HO(CH2)5C1 in an ammoniacal benzene solution, the compound CaHa(C4Ho)2SiO(CH2)sCl is obtained.

Example 6 103 grams of 5-chloropentanol-1 was dissolved in 300 m1. of benzene together with grams of ethyldimethylchlorosilane. Pyridine was added to the solution in small portions until further addition caused no precipitation of solids. The mixture was filtered and distilled to yield 108 grams of 5-chloropentoxy-1-dimethylethylsilane, boiling 110 C. at 21 mm.,

and specific refraction .2807.

Example 7 116 grams of 4-chlorobutoxy-l-trimethylsilane was added slowly to 16.5 grams of magnesium chips in absolute ether. The usual precautions were taken to guard against moisture and oxyen. Reaction proceeded slowly and continued until the magnesium dissolved. The resulting product was (CH3)aSiO(CH2)4MgC1. The ether solution was refluxed for one hour and there was no evidence of decomposition of the product.

Example 8 114 grams of 5-chloropentoxy-1-trimethy1- silane was added slowly to 16.5 grams of magnesium chips in absolute ether. During the reaction the usual precautions were taken to guard against moisture and oxygen. Reaction continued until the magnesium had dissolved and the resulting product was (CH:)3SiO(CH2)5MgCl. This material is stable in refluxing ether solution.

That which is claimed is:

1. A compound of the formula RaSiO (CH2) :MgCl

where R is selected from the group alkyl and phenyl radicals and x has a value from 4 to 5.

2. The compound of claim 1 wherein R is a methyl radical.

JOHN L. SPEER.

References Cited in the file of this patent Moody, Jour. Amer. Chem. Soc., vol. 72 (1950). p. 5754. 

1. A COMPOUND OF THE FORMULA 